A Prototype of a Tennis Playing Robot

U ovom radu, nastoji se replicirati poznata videoigra Pong u stvarnom svijetu. Za to je upotrijebljen robot složen od Fischertechnik dijelova. Robot se sastoji od dvije funkcionalne cjeline: mehanizma za pravocrtno gibanje i mehanizma za ispucavanje loptice na protivničku stranu. Potonji predstavlja veći izazov, a izveden je pomoću dva servomotora. Na njih su prispojeni kotači, koji rotacijom predaju energiju loptici. Dijelovi robota spojeni su na Raspberry Pi mikroračunalo. Igrač koristi VIDI X mikroračunalo koje nalikuje na joystick ili prijenosnu igraću konzolu - ima zaslon i tipke, pa je ideja bila upotrijebiti ga u tom stilu. Pritiskom odgovarajućih tipki, VIDI X šalje naredbe Raspberry Pi-u, koje on u svome programu procesira i zatim upravlja robotom. Za bežičnu komunikaciju VIDI X i Raspberry Pi-a, implementirana su dva rješenja: putem Bluetootha i Wi-Fi-a. Wi-Fi metoda temelji se na MQTT protokolu - VIDI X i Raspberry Pi podešavaju se kao klijenti, a istovremeno se na Pi-u pokreće broker koji djeluje kao poštanski sandučić gdje klijenti mogu odložiti i preuzeti poštu. Bluetooth podrazumijeva direktnu komunikaciju među uređajima. Primijenjena je BLE varijanta kako bi se dodatno umanjila potrošnja energije. VIDI X kreira BLE server, a Pi se povezuje i čeka na obavijesti. Iako su obje metode funkcionalne, Bluetooth rješenje preferirano je u ovom slučaju. Konačno, implementiran je ESP-NOW modul za komunikaciju dva VIDI X-a, kako bi se u partiji pratio rezultat. Rezultat je također prikazan na zaslonu VIDI X-a.This academic work attempts to recreate the well-known videogame Pong, in a physical environment. A robot was assembled using parts from Fischertechnik sets. Robot contains two main functional components: movement mechanism and ball-shooting mechanism. The latter is more challenging to design - that has been done using a couple of servomotors and attaching wheels to their axis. Rotating wheels pass kinetic energy to the ball upon contact. Motors and electrical elements are connected to Raspberry Pi microcomputer. The player shall be using VIDI X microcomputer, which resembles a joystick or a handheld console. It contains a screen and several buttons, so the idea was to utilise VIDI X in that regard. By pressing the designated buttons, VIDI X is instructed to relay certain information to Raspberry Pi, which Pi has to parse and use to control the robot. VIDI X and Raspberry Pi can communicate in multiple ways: Bluetooth and Wi-Fi were two methods chosen. Wi-Fi implements MQTT protocol, where VIDI X and Raspberry Pi were set up as clients, while a broker simultaneously ran on Pi, which receives and distributes the mail to clients accordingly. Bluetooth has no intermediary component - the devices communicate directly to each other. BLE variant was implemented to further save power. BLE server was created on VIDI X, to whom Raspberry Pi connects and awaits notifications, which occur when appropriate buttons are pressed. Both methods worked well, however Bluetooth is the preferred option. At last, ESP-NOW module was used to wirelessly connect two VIDI X. Purpose was to keep track of score at each device respectively, which is also displayed on the screen